COPD Flashcards
What causes airway narrowing/obstruction?
muscle spasm
mucosal oedema
airway collapse due to loss of support
tumour or foreign body stuck in lumen
What are the 3 aspects that make up COPD?
chronic bronchitis
emphysema
small airway inflammation (respiratory bronchiolitis)
Define chronic bronchitis.
Cough productive of sputum on most days for 3 months of at least 2 successive years
How does chronic bronchitis come about?
Chronic irritation (cigarette smoke/atmospheric pollution) leads to a defensive increase in mucus production with increase in numbers of epithelial cells (esp. goblet cells). This gives a role in sputum production and increased tendency to infection
Is chronic bronchitis reversible or non-reversible obstruction?
non-reversible
What can cause small airway inflammation in COPD?
Goblet cell metaplasia, macrophage accumulation and fibrosis (scarring) around bronchioles may generate functional obstruction
Define emphysema.
Increase beyond the normal in the size of the airspaces distal to the terminal bronchiole without fibrosis
What types of emphysema are there?
centriacinar (centrilobular)
panacinar (whole lobule affected)
Other types can occur localised around scars in the lung
How is emphysema diagnosed?
Difficult to diagnose
CT scan used - shows changes in lung density
What is the “dilation” in emphysema due to?
loss of alveolar walls not an increase in normal space
What can be found in the lungs of smokers and urban dwellers?
Carbon pigmentation
How does emphysema impair respiratory function?
- diminished alveolar surface area for gas exchange
- loss of elastic recoil so support of small airways is not apparent leading to tendency to collapse with obstruction
As COPD advances what does a decreased PaO2 lead to?
Dyspnoea and increased respiratory rate Pulmonary vasoconstriction (and pulmonary hypertension)
What are the 3 main epidemiological factors that relate to the development of COPD?
Smoking
atmospheric pollution
Genetic factors
What is alpha1- anti-trypsin deficiency?
an autosomal dominant genetic condition
- deficiency in alpha1- anti-trypsin leads to an increased number of elastases (enzymes produced by neutrophils and macrophages) which leads to the destruction of elastic alveolar walls (emphysema)
How does tobacco smoke indirectly inhibit alpha1- anti-trypsin?
Tobacco smoke Increases number of neutrophils and macrophages in lungand slows transit of these cells. This promotes neutrophil degranulation releasing elastase which inhibits 1 antitrypsin
What leads to mucous hypersecretion in chronic bronchitis?
Marker hypertrophy of mucous secreting glands and hyperplasia of goblet cells (caused by chronic inflammation from cigarette smoke)
In emphysema, which immune cells show a chronic inflammation?
neutrophils, macrophages and CD8+ T cells
How is COPD assessed?
Symptoms
spirometry - degree of airflow limitation
CXR - to exclude aditional diagnoses
risk of exacerbations
What are the symptoms of COPD?
chronic symptoms daily productive cough progressive breathlessness wheeze infective exacerbation - increased cough with purulent sputum
What are the signs of COPD?
tachyponea
use of accessory muscles
hyperinflation of chest
decreased chest expansion
what are emphysematous bullae?
Large (>1cm) closed off air spaces with trapped air seen on CXR
How is the severity of COPD expressed?
Mild - FEV1 50-80% off predicted
Moderate - FEV1 30-49% predicted
Severe - FEV1 <30% of predicted
What are the non-pharmacological interventions for COPD?
stop smoking encourage exercise treat poor nutrition or obesity influenza & pneumococcal vaccinations pul rehab/ palliative care
How is Mild COPD treated?
Salbutamol or ipratropium
How is moderate COPD treated?
Ipratropium or salmeterol and inhaled beclometasone (corticosteroid)
How is severe COPD treated?
Salmeterol and beclometasone and ipratropium and refer to specialist
What is the treatment for an acute exacerbation of COPD?
ABCDE IV access (FBC,U&Es, blood culture) O2 (88-92%) & ABG Oral prednisolone/ IV hydrocortisone Amoxicillin oral (if infective) Nebulised Salbutamol (bronchodilator) Physiotherapy to expel secretions
What are the complications of COPD?
Respiratory failure (type 2) Cor pulmonale (heart failure 2y to disease of the lung)
